Thousands of angry workers battled riot police with firebombs, rocks, pipes and clubs Saturday to protest a huge police attack that crushed a three-day strike at the world's largest shipyard. Police said at least 24 people were injured, 10 of them police officers, in violence that began when thousands of security officials stormed the Hyundai Heavy Industries Co. by land and sea. Police said 499 workers were arrested and that warrants were issued for six fugitive union leaders.

Thousands of riot police firing tear gas stormed the world's largest shipyard, clashing with striking workers barricaded inside and armed with homemade weapons. About 10,000 police poured through five gates leading into the huge seaside Hyundai Heavy Industries Co. shipyard in Ulsan, about 200 miles southeast of Seoul. About 20,000 of the shipyard's 24,000 employees are unionized.

An export boom that carried South Korea from poverty to the brink of entering the ranks of advanced industrialized nations over the last three decades has sputtered to an end, with no recovery in sight. A trade surplus that last year amounted to $8.9 billion has been all but wiped out, falling to a minuscule $600 million in the first 10 months this year. The U.S. trade deficit with South Korea that soared to $9.

Angry farmers and radical students demanding an end to U.S. food imports protested in about two dozen cities and rural areas, hurling rocks and firebombs at police. In Kunsan, protesters took their demands to the main gate of a U.S. Air Force base. About 2,000 demonstrators battled riot police at Konkuk University in eastern Seoul after they were prevented from protesting in the streets. "Drive out the Yankees," they chanted, charging that cheap U.S. imports threaten their livelihood.

Several hundred police officers using tear gas and a bulldozer stormed a sports equipment factory near the South Korean capital Sunday to arrest 67 striking workers. A police spokesman said 1,300 officers surrounded the factory while the bulldozer crushed a barricade set up at the gate after management asked them to disperse strikers occupying the premises since late April.

South Korean riot police stormed the country's biggest shipyard and arrested striking workers whose dispute has paralyzed production for over three months. At first light, under cover of a barrage of tear gas, thousands of police in combat gear assaulted the strikers' stronghold in the yard of Hyundai Heavy Industries Co. at Ulsan, on the southeast coast.

After a year of abstinence, Kim Woo Choong, the founder and chairman of the Daewoo Group, has started smoking again. "I quit until all our labor trouble broke out," said the 51-year-old entrepreneur who turned the tiny textile exporting firm that he co-founded with $9,000 in borrowed cash in 1967 into a $10-billion conglomerate. In a two-hour, 45-minute interview, however, labor strife was the only problem Kim cited for his group of companies or for South Korea.